The Seoul Central District Prosecutors' Office said Thursday that it has banned Nexon founder and holding company NXC Chairman Kim Jung-ju from leaving the country, over a scandal in which he allegedly granted favors to a senior prosecutor in buying the game company's stocks.

In March, it was discovered that senior prosecutor Jin Kyung-joon made over 12 billion won from selling off shares of the company which he had purchased at much lower prices in 2005.

At the time Jin said he had bought the shares with his own money, but later said he got the money from his mother-in-law.

Earlier this month, Nexon acknowledged that it had lent Jin and other buyers money to buy its stock.

The company said in a statement it was because the firm wished to conclude the deal swiftly and the buyers promised to pay back the money quickly, which they did.

Nexon did not receive interest on the money it temporarily provided to the buyers, igniting a controversy that the company granted favors to them.

The controversy was based on the ties between Kim and Jin, as they are college alumni and their families are close.

Suspicions were also raised over how Jin knew about Nexon selling its shares, because the company was unlisted at the time. Kim is suspected of having provided insider information to Jin. The game company's profits were snowballing at the time.

The huge profits Jin reaped were found in a mandatory asset disclosure of high-ranking officials. Jin, who had been chief of the Korea Immigration Service, stepped down from the post in April amid the controversy.